If you haven't read "The Intelligent Investor" yet or find it difficult to read, I recommend starting with this book.
Buffett said, “Many people who followed Graham’s teachings became rich, and it is difficult to find cases where they became poor.
“There are few people who can teach this,” he said.
I recommend this book in the hope that you too can see the light in the darkness that Buffett saw.
--- p.6, from the “Recommended Preface”

Getting into the habit of evaluating or quantifying your intrinsic value will help you reduce mistakes.
You should get in the habit of comparing the market price you pay with the intrinsic value you acquire to determine whether the price is low enough to buy.
You should buy stocks pragmatically, like buying groceries rather than perfume.

--- p.15, from the "Preface"

Even beginners can achieve decent, if not spectacular, investment results with just a little effort.
Even if you are a beginner, if you use your limited knowledge to think outside the box, it may lead to bad results.
--- p.15, from the "Preface"

Investing is about securing satisfactory returns while safeguarding your principal through thorough analysis.
Otherwise, it's speculation.
However, when the market crashes and the stocks reach their most attractive prices, they perceive stocks as speculative and risky. Conversely, when the market rises and reaches risky levels, they actually speculate but mistake it for investment.

--- p.20, Chapter 1.
From “Investment and Speculation”

An easy strategy is to allocate 50% of your portfolio to stocks and 50% to bonds.
However, it is better to adjust the proportion between 25% and 75% depending on market conditions.
For example, at the bottom of a bear market, you might increase your stock allocation to 75% and hold only 25% in bonds.
However, this method is not easy to implement because human nature is to follow the flow of the market.
In fact, even investment professionals who manage funds find it difficult to do this.
--- p.40, Chapter 4.
Among the “general portfolio strategies”

Even if the market appears to have reached a high or low, you should not trade hastily.
Investors should act like partners in the business.
You shouldn't be looking for daily stock prices or trying to find new partners.
Bond prices are unpredictable, but experienced investors can predict the relative magnitude of price fluctuations across bond types.
--- p.75, Chapter 8.
From “Investment and Market Fluctuations”

Speculators who want to make money in the short term use timing, while investors who can wait for an opportunity use pricing.
If the general public thinks they can make money by predicting the market, they are mistaken.

--- p.77, Chapter 8.
From “Investment and Market Fluctuations”

If you must rely on the advice of others, you should avoid using your imagination and stick to a conservative investment approach.
--- p.100, Chapter 10.
From “Investment Advice”

I have never seen a reliable security analysis that goes beyond simple arithmetic or basic algebra.
If calculus or advanced algebra appears in the analysis, it may be an attempt to disguise speculation as investment by presenting a plausible theory.
Investors need to understand the analyst's intent and be able to distinguish between sound and superficial analysis.
The analysis begins with the interpretation of annual financial statements.
--- p.111, Chapter 11.
From “Beginner’s Stock Analysis”

A stock's margin of safety is secured 'when the company's earnings power far exceeds the bond yield.'
For example, let's assume a company's earnings yield (EPS/stock price) is 9% and its bond yield is 4%.
These stocks offer a 5 percentage point annual advantage over bonds in terms of yield.
The company will pay out a portion of its excess returns to investors and reinvest the remainder to increase the company's value.
--- p.193, Chapter 20.
The most important concept is “Safety Margin”

The most business-like investment is the wisest investment.
It's surprising how many successful businessmen who adhere to sound principles completely ignore them when investing on Wall Street.
--- p.196, Chapter 20.
The most important concept is “Safety Margin”

The act of trading securities to make a profit is also a type of business, so it must be carried out while adhering to principles as if running a business.
(Omitted) You should not start a business unless you can clearly calculate that you can expect a reasonable profit.
Stay away from risky ventures that involve little gain and much loss.
The basis of investment should be solid numbers, not vague optimism.
--- p.197, Chapter 20.
The most important concept is “Safety Margin”

Use your knowledge and experience courageously.
If I have reached a conclusion based on facts and I believe that this judgment is sound, I will act on it even if it differs from what others think.
In investing, courage is the greatest asset only when accompanied by sufficient knowledge and judgment.
The average investor can succeed in investing even if he or she lacks these qualities, as long as he or she restrains his or her ambitions and sticks to safe, defensive investments.
--- p.198, Chapter 20.
The most important concept is “Safety Margin”

There are many ways to make and keep money on Wall Street, and one stroke of luck or a brilliant decision can be worth more than a lifetime of hard work.
However, to achieve good luck or make great decisions, you need to build up your skills over a long period of time.

--- p.204, from “Afterword”